Thang Long Highway in Hanoi opened to traffic on Sunday in an inaugural ceremony attended by Prime Minister Nguyen Tan Dung.
The highway is the longest in the country and stretches for 30 kilometers. It links Hanoi to the north-south Ho Chi Minh Highway and other localities in the northern region, the government said in a report on its website.
It cost more than VND7.5 trillion (US$386.5 million) to build the road, which has six lanes and a total width of 140 meters.
Speaking at the ceremony, Prime Minister Nguyen Tan Dung hailed the efforts of the project management board and contractors to complete the highway on schedule to celebrate the millennium anniversary of the capital city.
He also acknowledged the cooperation and support of local residents for the project.
Dung said the unifinished parts of the project needed to be completed soon to maximize the benefits for Hanoi and its neighbors.